On Thu, Oct 15, 2015 at 12:30:36AM +0800, Leo Yan wrote:
Hi all,
Below are raw power data on Hikey board; with this power data i'd like to create the power model for Hikey.
- Measure method:
On Hikey board, we cannot measure buck1 which is dedicated for AP subsystem; so turned to measure VDD_4V2 to remove R247 and remount shunt resistor 470mOhm. At a result, the power data includes many other LDO's power data.
+--------------+ +-------------+ 4.2v | | Buck1 | |---- Shunt Resistor --->| PMIC: Hi6553 |------>| SoC: Hi6220 | ^ ^ | | | ACPU | | | +--------------+ +-------------+ |-> Energy Probe <-|
Just reminding and correct one thing at here. If you are using ARM energy probe, there have limitation for "voltage between the two sense leads, limited to 165mV" (quoted from Andy's slides arm-energy-probe-101.pdf), so should change to use 33mOhm resistor.
Otherwise, when 8 CPUs run at high OPP (such like 960Mhz or 1.2GHz), it's very easily to reach the measurement limitation. Using 33mOhm will have no this issue.
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Thanks, Leo Yan